Weld Overlay Limit
Weld Overlay Limit
(OP)
Does the ASME Code (Division 1 or 2) limit the amount of weld overlay that could be used on a component to increase the overall thickness to handle a higher pressure? Example, if I had a 12" Diameter Carbon steel shell that is 1" thick, is there a limit to how much weld overlay could be put on it for increasing the thickness? Not really a practical thing necessarily to do of course, but more of a general question of what the Code would allow.





RE: Weld Overlay Limit
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P.E. Metallurgy, Plymouth Tube
RE: Weld Overlay Limit
RE: Weld Overlay Limit
RE: Weld Overlay Limit
RE: Weld Overlay Limit
I'm not aware of explicit limits to weld buildup in VIII-1, certainly weld buildup is mentioned in UW. For example, UW-16(c)(1) explicitly mentions the use of weld buildup for opening reinforcement. While UW-42 has limits, I don't see that section as limiting the use of weld buildup outside the scope of this particular paragraph.
I haven't looked at Div. 2 in this regard.
RE: Weld Overlay Limit
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Weld Overlay Limit
ASME VIII Div 2 Para 3.3.6 has the same requirements, pointing to para 4.1.9 for the same formula for calculating with weld overlay thickness included.
It is non-integrally attached linings for which no credit on thickness can be taken.
RE: Weld Overlay Limit
RE: Weld Overlay Limit
Incorrect. If the weld overlay is of equal to or greater strength than the base metal you most certainly can take credit for pressure retaining thickness assuming a strength ratio of 1 (overlay strength to BM strength). You can't take credit for stronger overlay material.
RE: Weld Overlay Limit
I have worked with people that have taken credit for a clad layer (explosive bond).
There have been discussions about what would be involved in taking credit for higher strength.
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P.E. Metallurgy, Plymouth Tube
RE: Weld Overlay Limit
Cladding can also be used for thickness calculations, but it comes with some additional testing requirements, see section UCL-11(c).
Briefly, this paragraph lays out some additional testing that must be performed to ensure adequate shear strength between the cladding and base metal. This paragraph discusses tests such as "Bond Strength" test as described in SA-263, SA-264, and a "Shear Strength" test.
In our experience, many customer specs specifically prohibit the use of any cladding in code calculations. As such, I know of these rules, but have never actually applied them...
RE: Weld Overlay Limit
RE: Weld Overlay Limit
Regards
r6155
RE: Weld Overlay Limit
RE: Weld Overlay Limit
Very common construction in S&T exchangers, I don't know about other classes of work. As I said earlier, the thickness of the clad / overlay is rarely accounted for as pressure retaining.
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Weld Overlay Limit
Regards
r6155
RE: Weld Overlay Limit
But the original poster was specifically asking about adding weld metal to increase the PV wall thickness to add additional metal for pressure vessel qualification at a higher pressure. And that particular purpose - even assuming you can add enough metal by weld overlays and NDE and more weld overlay and final grinding to get a verified thickness - is many times more expensive than the original metal purchase price.
RE: Weld Overlay Limit
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Weld Overlay Limit
My reply: NO
Regards
r6155
RE: Weld Overlay Limit